MUC1 and small cell lung carcinoma: Previous studies have shown that MUC1 is highly expressed in patient‐derived SCLC cell lines, suggesting its potential as a biomarker for SCLC.[36] Other group reported that miR‐543 regulates cell proliferation and migration via MUC1 in SCLC cells.[37] Notably, MUC1 has been reported to promote CSC self‐renewal and tumorigenicity in SCLC by activating the myelocytomatosis viral oncogene homolog (MYC)–E2 transcription factor (E2F)–NOTCH2 signaling.[38] However, the effect of MUC1 on CSC division patterns remains unclear.